Directional control means for highway crossing signals



J. A. QUINLAN Nov. 2 1948.

DIRECTIONAL CONTROL MEANS FOR HIGHWAY CROSSING SIGNALS Y Fi led Nov. 22,1946 QTL r v A m1 Q .fib NM 7 is MN BO v8 SK TR mm mm Jarep v \N Q QNESSR Q W N Q it HIS ATTORNEY Patented Nov. 2, 1948 DIRECTIONAL CONTROLMEANS FOR HIGH- WAY CROSSING SIGNALS Joseph A. Quinlan, Wilkinsburg,Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., acorporation of Pennsylvania Application November 22, 1946, Serial No.711,586

6 Claims. 1

My invention relates to directional control means for highway crossingsignals, and more particularly to directional control of highwaycrossing signals by track instruments.

At some locations on a railway it is not practical or economical to usetrack circuits and it is necessary to resort to the use of trackinstruments to detect the presence of trains. When track instruments areused to control highway crossing signals, it is necessary to provide adirectional control so that a train passing over a track instrument inapproaching a highway intersection will initiate operation of thehighway crossing signal, but that operation of the track instrument by atrain moving awa from the intersection does not operate the signal.While directional track instruments are known, they are not entirelysatisfactory.

Accordingly, a feature of my invention is the provision of an improveddirectional control of a highway crossing signal by non-directionaltrack instruments.

Other features, objects and advantages of my invention will appear asthe specification progresses.

The foregoing features, objects and advantages of my invention I attainby providing a novel relay and circuit arrangement governed by a groupof track instruments located at different preselected points each sideof a highway intersection.

I shall describe one form of apparatus embodying my invention and shallthen point out the novel features thereof in claims.

In the accompanying drawing, which is a diagrammatic view showing oneform of apparatus embodying my invention, the reference characters lband lb designate the track rails of a stretch of railway track overwhich trafiic moves in either direction, and which stretch isintersected by a highway H. A highway crossing signal S is providedadj'cent the intersection, the signal S being here shown as a flashinglight signal, although other types of highway crossing signals can beused.

A group of track instruments A, B, C, D, and E are provided, eachindividual instrument being operatively associated with the track rails.According to my invention the track instrument C is located adjacent theintersection with the highway, the instruments A and B arelocatedrelatively close together to the left of the intersection as viewed inthe drawing, and the track instruments D and E. are located relativelyclose together to the right of the intersection. The distance the trackinstrument A is placed from the intersection is predetermined accordingtothe maximum permissible train speed for eastbound trains, that is,trains moving from the left to the .right, and the required warningperiod of the signal S prior to the arrival of a train at theintersection. Similarly, the distance the track instrument E is placedfrom the intersection is predetermined according to the maximumpermissible train speed for westbound trains and the required period ofwarning operation of the signal. For example, if the maximum permissibletrain speed is miles per hour, or 134 feet per second, and a warningperiod of 20 seconds of the signal is required before the train reachesthe intersection, the instruments A and E will be placed 2,680 (134 x20) feet from the intersection. The track instruments B and D arepositioned about feet from the track instruments A and E, respectively,and on the side toward the intersection. In the event very long trainsare operated, the track instruments A and E would preferably be locatedfrom the intersection a distance greater than the longest train to beoperated, and the warning period may be correspondingly increased.

These track instruments are shown conventionall for the sake ofsimplicity, since they can be of any one of several well-known forms.For example, these track instruments may be similar to the structuredisclosed in Letters Patent of the United States No. 2,083,288, grantedJune 8,1937, to Herbert L..Bone, for Track rail contractors. It issufficient for the present application to point out that each trackinstrument is attached to at least one track rail for operation of acircuit contact as a train wheel passes over the rail at the point theinstrument is attached thereto, the contact being operated irrespectiveof the direction in which the train is moving. That is to say each trackinstrument is non-directional. Each track instrument A and E is providedwith a contact biased to a closed position and operated to an openposition when a train moving in either direction passes over theinstrument. Each track instrument B, C, and D is provided with a contactbiased to an open position and closed when a train moving in eitherdirection passes over the track instrument. It is believed that thecircuits and relays associated with this group of'track instruments toobtain directional control 'of the highway crossing signal S can best beunderstood from a description of the operation of the apparatus. I

It is to be pointed out that in several instances relay contacts areshown in the drawing remote from the relay winding in order to simplifythe drawing. In each such instance the contact is identified by thereference character of the assoelated relay plus a distinctive numeraland the contact is shown in the position corresponding to the normalcondition of the relay.

Normally, that is. when no train is Within the limits or the stretch oftrack involved, the apparatus occupies the position shown in the draw:ing. Under this normal condition a master stick relay AES is retainedenergized by a stick circuit which extends from terminal BA of a sourceof current such as a battery not shown through contact ill of trackinstrument A, line wire ll, contact I2 of track instrument E, line wirelg, front contact M- of relay AES, and the winding of the relay to theother terminal NA of the same source of current. The remaining relaysare all deenergized and the signal S is inactive.

I shall first consider the manner of initiating the operation of thesignal S when an eastbound in ap ro he he in e sect-i n- .W the leadingwheel of the eastbound train passes over the trackins-trument A,the-contact it is actuated to its n Po t on and th s o e e s c coil; ofmaster relay Afifi and that relay is deenersizcd and released and thenremains released until a pick-up circuit to be described hereinafter scomp eted- T e rele se o ma relay AES close back contact l 5 completesan obvious circuit for a flasher relay of standard form, and that relayis set into operation to alternately operate its two contacts l6 and H.The release of relay ABS closing Toacl; cont-act 2.5 also completes aeenes t e o a nal e e ies ci c t a source Q P cr i el ct by the er nal2; d (3 Thus the flash r ela F operated, t e two lamp l5 and o ign l S ae alter e 1- lu rninatedpy power from the BX-CX source, and thisflashing of the lamps l8 and 19 serves as a warnin ediee en o i h use sf the p each -tihs ees beim trem- The leading train Wheel of thiseastbound train ne t s aces the rack in t n B Closing its s A and 3 arelocated relatively close together. The contact 20 is included in thecircuit for a relay 13D, to be referred to hereinafter, but

rent 3.? performs no useful function at this time and t sta na i n ee mic de d A the easthound train approaches the intersection,

the operation of the signal S is continued, due to the fact that theplaster relay AES remains deenrsi sd and he flasher l y F s Suppliedwith power.

' I shall next consider the manner Joy which the warning operation ofthe signal S is continued until the rear of the train passes over theintersection and the operation isthen stopped. When the train reachesthe intersection, the leading train wheel actuates the tracl; instrument0 closing its contact ,2! to complete a simple circuit for a slowrelease relay GP and that relay is energized. Relay CE is provided witha resistor 22 and a capacitor th; my oll i' ui et een mot er of e r W 1tl y Q itt up an alt rn e c t for its asher. relay i closed a rom c c 24of relay CP and an alternative connection to the t et 29 it-temgrecalled that the two instrw' connected in eries across the winding of.the'

mL in power source is completed at front contact at of relay CP. Itfollows that the operation of the si nal S is continued while the trainpassing over the track instrument C which is adjacent the intersectionunless the train actually stops in a position where no wheel is over theinstrument C. When the last wheel of the train passes over the trackinstrument C, it is restored to its normal condition and the relay CP isdeenergized and released at the end of its slow release period so thatthe alternative circuits for the flasher relay FR and the supply ofpar-"er for signal opened to stop the operation of the signal, providingof course that the master relay AES has in the meantime been reenergizedin a manner to he now explained.

The reenergizing of the master AES is accomplished by operation or"stick relays CS and CSP and a time element relay the operation beinginitiated relay CP. The relay CS is energized by current flowing fromterminal BA through front contact 25 of relay CP, normally closed checkcontact 23 of the time el-ercent relay CTE, and winding of relay CS tothe terminal NA, and the relay CS is picked up to close a stick circultincluding its own front contact 29 2 back contact of the master relayAES. Relay CS on picking up, closing front contact completes an obviouscircuit for the time element relay GTE. Relay CTE is a time elementrelay preferably of the thermal type, wherewith a normally open contactis closed at the expiration of a fixed period after the heating elementof the relay is supplied with power. Relay C'IE is proportioned for anoperating period shown in the drawing as being 15 seconds, but othertime intervals can be used. Thus it can he said of the time elementrelay CT that immediately after current is sup lied to its heatingelement as, its check contact 28 is opened and at the end of a 15seconds operating period its contact 35 is closed. When the relay CS i-picked up, closing front contact a pick-up circuit for relay CS? iscompleted, this pick-up circuit also including a resistor 33. Relay CSPon picking up completes a stick circuit at its own front contact 3% andit also closes a front contact 36 to prep-are a pick-up circuit for themaster relay ABS and which pick-up circuit also includes contact 35 ofrelay CTE. Thus, at the end of the 15 seconds operating period for therelay CTE, the closing of contact 35 of relay TE complete the pick-upcircuit for the master relay AES and that relay is reenergized andpicked up. Relay AES on picking up closes its stick circuit which Wasdescribed hereinbefore, and it is retained in its normal energizedcondition by the stick circuit since contact it of the track instrumentA. was reclosed when the rear of the train passed that point. The masterrelay AES on pick ng up to open the back contacts 55, 2t and 39, opensat the contacts l5 and 26 the first operating circuit for flasher relayPR and the first power connection for the signal S. The opening of backcontact 3i opens the stick circuit for relay CS and relay CS onreleasing opens front contact 3! through which power is supplied to thetime element relay CTE, and also opens the pick-up circuit for the relayCSP at front contact 32.

There may be a thermal time lag in the restoring of contact 35 to itsopen position after the heating element 48 of relay GTE is withoutpower. Such time lag in the restoring of contact 35 does not retain thepick up circuit of the master relay AES closed unduly long because whencontact 35 is closed it places a shunt across relay CSP and that relayis shunted in a short period of approximately 1 second, and with relayCSP released the pick-up circuit of the master relay AES is open atfront contact 36 of relay CSP. This prompt opening of the pick-upcircuit of the master relay assures that a second or following eastboundtrain cannot pass track instrument A and relay AES does not respondthereto.

It follows that as the eastbound train recedes from the intersection,the warning operation of the signal S is stopped and the relays andcircuits are restored to their normal condition ready to respond to afollowing eastbound train.

I shall next consider the operation of the apparatus as the eastboundtrain passes over the track instruments D and E. When the leading wheelof the train operates track instrument D, closing its contact 31,current flows from terminal BA through contact Ill of track instrumentA, line wire ll, contact I2 of track instrument E, contact 31 of trackinstrument D, line wire 38 and winding of relay BD to terminal NA, andthe relay ED is energized and picked up. The closing of front contact 39of relay BD completes an alternative circuit path for the stick circuitof 'the master relay AES, so that relay AES is retained energized whenthe eastbound train passes over the track instrument E opening itscontact I2 which is interposed in the normal stick circuit of the masterrelay. A resistor 40 and a capacitor M in series are connected acrossthe winding of relay BD and that relay is provided with a slow releaseperiod sufiicient to assure that the relay is not released in the casethe contact 3? of instrument D is opened momentarily between :1.

trucks of the eastbound train and also the relay is not released whilethe rear of the train is moving between the track instruments D and E.It is apparent from the foregoing description that the apparatus heredisclosed provides directional control for the highway crossing signal Sso that the signal is operated to give a warning indication while theeastbound train approaches the intersection and passes over theintersection and the warning operation is discontinued while the trainrecedes from the intersection and passes over the track instruments Dand E provided for westbound trains.

Operation of the apparatus for a westbound train is similar to theoperationior an eastbound train and the operation for a westbound trainneed not be explained except to point'out that when the leading wheel ofthe westbound train actuates track instrument E opening its contact [2,the stick circuit of the master relay AES is' opened and that relay isreleased to energize flasher relay FR and supply power to the signal Swhereby the warning operation of the signal is initiated. Operation ofthe track instrument D by the westbound train efiects no useful func-'tion. Operation of the track instrument C by the westbound trainenergizes relay GP to continue operation of the signal until the rear ofthe train passes completely over the intersection and 7 the trackinstrument C is restored to its normal condition. Energization of therelay CP also sets in motion operation of the relays CS, CTE and CS1? toreenergize the master relay'A'ES in the manner explained hereinbefore.Operation ofthe track instrument B as the westbound train recedes fromthe intersection closing contact 2%) completes a circuit for relay BDand that relay is picked up closing front contact 39 which closes thealternative circuit path for the stick circuit -of the master relay AESso that the master" relay is" not released as the westbound train movesover the track instrument A. l

To sum up the operation, the warning operation of the signal S isstarted when an eastbound train reaches track instrument A and when awestbound train reaches track instrument E. The warning operation of thesignal is continued in either case until the lapse of a given periodafter the rear of the train passes the track instrument C. Furthermore,operation of the signal is avoided when the track instrument E isoperated by an eastbound train and when the track instrument A isoperated by a westbound train.

Atime element relay ATE and another relay AET areprovided to restore theapparatus to its normal condition in the event a loss of power occurs orin the event the stick circuit for the master relay AES is inadvertentlyopened for a moment. Assuming a loss of power occurs and the masterrelay AES is released, a circuit is completed from terminal BA throughback contact 62 of relay AES, heating element 39 of relay ATE and backcontact is. of relay AET to the terminal NA and the time element relayATE is set into operation when power is reapplied. The operating periodof the time element relay ATE is made relatively long and in the drawingit is indicated as being a period of 3 minutes, but other periods can beused. This operating period for the relay ATE is made longer than thenormal time required for a train to pass through the stretch of track,that is, to approach and pass over the intersection. When relay ATE hasoperated its fixed period of time, contact 44 is closed to complete anobvious pick-up circuit for relay AET and that relay is picked up andcompletesa stick circuit for itself through its own front contact t5 andback contact all of the master relay AES. With relay AET picked upopening back contact 43, the time element relay ATE is without power andit is restored to its normal position after a short time lag. Theclosing of check contact 46 of the time element relay ATE completes analternative pick-up circuit for the master relay through contact as ofthe time element relay and front contact 41 of relay AET, with theresult the master relay is restored to its energized condition closingits stick circuit by which it is normally retained energized. When themaster relay AES is picked up opening back contact to, the relay AET isdeenergized and restored to its normal condition.

It is to be noted that in the event a train stops and remains in theapproach section to the intersection, the operation of the signal willbe stopped after a period due to the action of the relays ATE and AET inthe manner just explained. In the event this train later approaches theintersection the signal will be operated while the train is passingthrough the intersection due to the operation of the track instrument C.

Apparatus such as here disclosed has the advantages that dire-ctionalcontrol is provided for highway crossing signals through the medium ofnon-directional track instruments of relatively simple construction.

Although I have herein shown and described but one form of directionalcontrol means for highway crossing signals embodying myinvention, it isunderstood that various changes and modifications'may be made thereinwithin the scope of the appended claims without departing from thespirit and scope ofmy invention..

aeeasae 6 Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track intersected by a highway,a highway crossing signal located at the intersection, a first trackinstrument located at a selected point to one side of the intersection,said track instrument having a contact biased to a closed position andopened by a train passing over the instrument, a master relay having astick circuit completed through said contact of the first trackinstrument, operat-- ing circuit means having a first path governed bysaid master relay to operate said signal when the master relay isdeenergized, a second track instrument located adjacent saidintersection'and having a contact biased to an open position and closedwhen a train passes over that instrument, a slow release relay energizedthrough said contact of the second track instrument, a second circuitpath of said operating circuit means governed by a contact of said slowrelease relay to operate the signal when the slow release relay ispicked up, a first restoring circuit means including a time elementrelay having a contact closed in a preselected relatively short periodof time and governed by said slow release relay when picked up, a secondrestoring circuit means including a time element relay having a contactclosed in a preselected relatively long period of time and governed bysaid master relay when released, and a pick-up circuit means for saidmaster relay and made efiective when the contact of either of said timeelement relays is closed.

2. In combination, a stretch of railway track intersected by a highway,a highway crossing signal located at the intersection, a first trackinstrument located at a selected point to one side or the intersection,said track instrument having a contact biased to a closed position andopened by a train passing over the instrument, a master relay having astick circuit completed through said contact of the first trackinstrument, operating circuit means having a, first path governed bysaid master relay to operate said signal when the master relay isdeenergized, a second track instrument located adjacent saidintersection and having a contact biased to an open position and closedwhen a train passes over that instrument, a slow release relay energizedthrough said contact of the second track instrument, a second circuitpath of said operating circuit means governed by a contact of said slowrelease relay to operate the signal when the slow release relay ispicked up, restoring circuit means for said master relay and including afirst and a second stick relay and a time element relay, said timeelement relay having a contact which is closed only after the relay issupplied with power for a given time interval, said first stick relayhaving a pick-up circuit including a front contact of said slow releaserelay and a stick circuit including a back contact of said master relay,said second stick relay having a pick-up circuit including a frontcontact of said first stick relay and a stick circuit including aresistor, means including a front contact of said first stick relay tosupply power to said time element relay, a pick-up circuit includingsaid time element relay contact and a front contact of said second stickrelay to reenergize said master relay, and said time element relaycontact disposed when closed to shunt said seccnd stick relay.

3. In combination, a stretch of railway track intersected by a highway,a highway crossing signal located at the intersection, a first trackwheel passes over the instrument, a master relay having a normallyclosed stick circuitincluding said first track instrument contact,operating means for said signal governed by said master relay to operatethe signal when the master relay is deenergized, a second trackinstrument attached to a rail of the stretch ata point relatively nearthe first track instrument on the side toward the intersection, saidsecond track instrument having a contact biased to an open position andclosed when a train wheel passes over that'instrument, a slow releaserelay energized through said second track instrument contact, and analternative path including a front contact of said slow release relayfor said stick circuit-of said master relay to retain the master relayenergized when a train passes over the first track instrument in recedng from the intersection.

4. In combination, a stretch of railway track intersected by a highway,a highway crossing signal located at the intersection, a first, a secondand a third track instrument which a train passes in the order named inapproaching the intersection; said first track instrument having acontact biased to a closed position and opened when 'a train wheelpasses over the instrument and each said second and third trackinstruments having a contact biased to an open position and closed ;whena train wheel passes over the instrument,

a master relay having a normally closed stick c rcuit including saidfirst track instrument contact, circuit means governed by said masterrelay when deenergized to operate said signal, a slow release relayhaving an energizing circuit including said third track instrumentcontact, another circuit means governed by said slow release relay whenenergized to operate said signal, another slow release relay havingan'energizing circuit including said second track instrument contact,and a circuit path including a front contact of said another slowrelease relay to shunt said master relay stick circuit around said firsttrack instrument contact.

5. In combination, a stretch of railway track intersected by a highway,a highway crossing signal located at the intersection; a first, a secondand a third track instrument which a train passes in the order named inapproaching the intersection, said first track instrument having acontact biased closed and opened by a passing train and each said secondand third track instruments having a contact biased opened and closed bya passing train, a master relay having a normally closed stick circuitand a normally open pick-up circuit, said stick circut including saidfirst track instrument contact, a first slow release relay hav ing anenergizing circuit including said third track instrument contact,operating means for said signal controlled by alternative circuit-pathsone of which includes a back contact of said master relay and the otherof which paths includes'a front contact of said first slow releaserelay, means including another relay and a time element relay controlledby said first slow release relay when energized to momentarily closesaid pick-up circuit in a predetermined time interval to reenergize saidmaster relay, a second slow release relay having an energizing circuitincluding said second track instrument contact, and a circuit pathincluding a first contact of said second slow release relay to shuntsaid stick circuit or the master relay around said first trackinstrument contact.

6. In combination, a stretch of railway track intersected by a highway,a highway crossing signal located at the intersection, a first and asecond track instrument on one side of the intersection and operated inthe order named by a train approaching the'intersection on saidone side,a third track instrument located adjacent the intersection, afourth anda fifth track instrument on the other side of the intersection andoperated reverse to the order named by a train approaching theintersection on said other side, said first and fifth -track instrumentseach having a normally closed contact which is opened by a passingtrain; said second, third and fourth track instruments each having anormally open contact which is closed by a passing train, a master relaynormally energized by a stick circuit including in series the contactsof said first and fifth track instruments, a slow release relay havingan energizing .circuitincluding the contact of said third trackinstrument, operating means for said signal having alternate paths oneincluding a back contact of said master relay and one including a frontcontact of said slow release relay, circuit means including a timeelement relay and controlled by said slow release relay when energizedto close a pick-up circuit for said master relay, another slow releaserela energized through the contacts of said second and fourth trackinstruments in multiple, and a circuit path including a front contact ofsaid another slow release relay to shunt said stick circuit of themaster relay around the contacts of said first and fifth trackinstruments.

JOSEPH A. QUINLAN REFERENCES CETEE) The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Name Date Linker Feb. 13, 1917 FOREIGN PATENTSCountry Date Austria Mar. 25, 1937 Switzerland June 1, 1937 Austria Mar.25, 1938 Number Number

